Conventionally, various angle detection apparatuses using magnetic sensors such as Hall elements have been known. It is widely known that, in these conventional angle detection apparatuses, an offset error included in a Hall element output is cancelled by adopting a constitution based on a so-called spinning current method. This spinning current method is described in, for example, Alberto Bilotti, Gerardo Monreal, and Ravi Vig, “MONOLITHIC MAGNETIC HALL SENSOR USING DYNAMIC QUADRATURE OFFSET CANCELLATION”, published by Allegro MicroSystems, Inc., Technical Paper STP 97-10.
In addition, as described in U.S. Pat. No. 5,942,895, it is known that accurate magnetic detection is performed by arranging Hall elements under a magnetic flux concentrator.
However, when angle detection for a magnetic field is performed according to these conventional techniques, since it is necessary to, for example, apply predefined digital processing to each Hall output to finally perform arithmetic processing for obtaining angle information, enlargement of a circuit size and an increase in production cost are inevitable problems.
In particular, when attempting to realize a very small angle detection apparatus by a semiconductor process or the like, simplification of a circuit configuration and reduction in size of an entire apparatus are problems that must be solved by any means.
Thus, in view of the above-described points, it is an object of the present invention to provide an angle detection apparatus and an angle detection system that allows for accurate angle detection, regardless of a simplified circuit configuration.